Showing papers by "Alberto Cordero-Dávila published in 2007"
TL;DR: To verify the hypothesis that the frictional coefficient is a constant value, the dragging forces applied to a tool as a function of the relative speed between a rotating glass and the tool center were measured.
Abstract: According to Preston [J. Soc. Glass Technol. 11, 214 (1927)], the wear on a glass point in the polishing process is proportional to the work given by frictional force between glass and tool. He supposed that the frictional coefficient is a constant value. To verify this hypothesis, we measured the dragging forces applied to a tool as a function of the relative speed between a rotating glass and the tool center. To reproduce these experimental results, it was necessary to propose a new model, for which the frictional coefficient has a Gaussian dependence with relative speed. Therefore the wearing Preston equation has to be modified in order to include the frictional coefficient as a function of the relative speed.
16 citations
TL;DR: A design of petal tools that are used to generate conic surfaces from their nearest spheres and that correct the profile of a surface that is polished are presented.
Abstract: Two constraints in the design of a petal tool are, the angles that define it must all be positive, and wear must never be greater than the desired wear. The first constraint is equivalent to that of the positive dwell times of a small solid tool. In view of this foregoing, we present a design of petal tools that are used to generate conic surfaces from their nearest spheres and that correct the profile of a surface that is polished. We study optimal angular sizes of a petal tool, which are found after we use linear programming to calculate the optimal dwell times of a set of complete annular tools placed in different zones of the glass surface. We report numerical results of designed petal tools.
6 citations
03 Dec 2007
TL;DR: In this article, a linear array of independent sub-tools is used to make an adaptive lens from plastic and elastic material, its focal distance can be changed by appling radial forces at the lens border ring.
Abstract: An adaptive lens can be made from plastic and elastic material, its focal distance can be changed by appling radial forces at the lens border ring. To make these kind of lenses it is necessary to figure molds. However, these molds can not be figured by using rigid tools for rapid surfaces. Then we are developing a new technique based in a linear array of independent sub-tools. A linear tool consists of subtools, the pressures of each one can be regulated according to the measured surface errors. The pressures are given by weights put over each sub-tool. By using genetic algorithms the pressure values of each subtool have been calculated in order to obtain the optimal wear. They are shown numerical and experimental results for several axisymmetrical surfaces.
1 citations